In recent years considerable effort has been made in attempting to reduce the weight of motor vehicles, generally as a fuel-saving measure. It has already been proposed to reduce vehicle weight by substituting light metal alloys and especially aluminum alloys for much of the steel which has hitherto been used in vehicle bodies and chassis.
Naturally, attempts have also been made to substitute light metal wheels for the iron or steel wheels which have generally been employed.
Emphasis has thus far been placed on the use of aluminum wheels which can be fabricated in a variety of ways, generally by casting, forging or some other techniques.
For example, it is known to fabricate aluminum wheels by a low-pressure die-casting process using casting alloys such as AlSi12, AlSi12Mg and AlSi7Mg.
Forged alloys for the production of wheels generally make use of AlMg1wa.
In a third technique as used heretofore, an aluminum wheel is fabricated from aluminum sheet or strip in the same manner as conventional steel wheels. Thus the felly or rim is formed by buttwelding the ends of a band, bent into a cylindrical configuration, and rolling the resulting ring to the desired profile. The wheel disk is stamped from the band and deepdrawn to the desired configuration and the two parts are joined together by welding.
The weight saving is greatest with the latter approach although the strength and stability characteristics of the resulting wheel are not always satisfactory.